TASHKENT: Authorities in Uzbekistan are investigating GM Uzbekistan, a venture part-owned by U.S. carmaker General Motors, over losses incurred by its Russian business, an executive at the Russian unit told Reuters on Tuesday.

"The company (GM Uzbekistan) is being investigated because the Russian distributor was unable to repay its debt," said Yelena Kuznetsova, director of marketing at the Russian representative office for Ravon, GM Uzbekistan's brand aimed specifically at the Russian market.

Kuznetsova said the Russian distributor had failed to pay GM Uzbekistan by the March deadline for cars shipped to Russia last year, because it had absorbed losses from the rouble's sharp depreciation over the last two years and could no longer obtain credit from banks.

The rouble has lost more than half of its value against the dollar since late 2014 as the price of oil, a key Russian export, plunged.

Kuznetsova did not say how big the debt was and could not confirm a report saying Tokhirjon Jalilov, former chief executive of GM Uzbekistan, had been arrested as part of the probe.

Uzbek news website UzMetronom, which carried the report this month, is privately-owned and Uzbek official media have said nothing about the investigation or arrest.

GM Uzbekistan said Jalilov left the company last month but declined to comment on the investigation. Uzbekistan's prosecutor general's office and the National Security Service said they were not involved, while the Interior Ministry declined to comment. Jalilov could not be reached for comment.

Detroit-based General Motors also declined to comment on the investigation. The U.S. firm has a 25 percent stake in GM Uzbekistan which it obtained as a result of its the acquisition of South Korea's Daewoo Motor Co.